Enumerates constants that determine a locale-specific date and time formatting pattern. These constants are used when
constructing a DateTimeFormatter object or when calling the DateTimeFormatter.setDateTimeStyles() method.

The CUSTOM constant cannot be used in the DateTimeFormatter constructor or the
DateFormatter.setDateTimeStyles() method.
This constant is instead set as the timeStyle and dateStyle property as a side effect of
calling the DateTimeFormatter.setDateTimePattern() method.